A review of the normal physiology of sodium, potassium, and water. Major topics covered include the renin angiotensin aldosterone system, the hypothalamic pituitary adrenal axis, ADH (antidiuretic hormone), and the natriuretic peptides.
over 5 years ago
A website created especially for healthcare students to encourage learning of embryology, malformation and its clinical implications. The package aims to: reinforce and build upon current healthcare curriculum content for embryological teaching of head development, to complement and enhance current teaching/learning/revision for relevant examination(s), to include interactive elements such as self-tests in order to improve learning and retention of knowledge, and finally, to illustrate aspects of malformation for diagnostic/clinical teaching purposes
over 8 years ago
It is understandable why resume writing is daunting for most students – they haven’t achieved many significant things at such young age and they have difficulties to present usual things as something extraordinary. However, you shouldn’t give up on your efforts, because you will be surprised by all things your potential employers consider valuable. All you have to do is find the right way to demonstrate your achievements and relate them to the job you are applying for. The following tips will help you write a great resume that will represent you as an ideal candidate for every employer. 1. Start the process by listing your experiences. You cannot tackle the challenge right where it gets most difficult, so you should gradually work your way towards the precise professional language. Start with brainstorming and create a list of all experiences you consider significant. You can draw experiences from all life aspects, such as school, academic activities, internships, prior employments, community service, sports, and whatever else you consider important. Look at that list and distinguish the most motivating experiences that led you to the point where you currently are. 2. Target the resume towards the job. Sending the same generic resume to all potential employers is a common mistake students do. You should tailor a custom-written resume for each job application, representing experiences and skills that will be relevant for the position you’re applying for. 3. Present yourself as a dynamic person. Find the most active components of your experiences and present them in the resume. Focus on action verbs, because they are attention-grabbing and make powerful statements (trained, evaluated, taught, researched, organized, led, oriented, calculated, interviewed, wrote, and so on). 4. Mark the most notable elements of your experiences and use them to start your descriptions. An employer couldn’t care less about the mundane aspects of college or internships, so feel free to leave them out and highlight your persona as a professional who would be a great choice for an employee. 5. Show what you can do for the organization. Employers are only looking for candidates who can contribute towards the growth of their companies, so make sure to portray yourself as someone who can accomplish great things in the role you are applying for. You can do this by reviewing your experiences and highlighting any success you achieved, no matter how small it is. 6. Don’t forget that your most important job at the moment is being a student. While you’re a student, that’s the most important aspect of your life and you should forget to mention that you are an engaged learner in your resume. Include the high GPA and the achievements in your major as important information in your resume. 7. Describe the most important academic projects. At this stage of life, you don’t have many professional experiences to brag about, but your academic projects can also be included in your resume because they show your collaborative, critical thinking, research, writing, and presentation skills. 8. Present yourself as a leader. If you were ever engaged as a leader in a project, make sure to include the information about recruiting and organizing your peers, as well as training, leading, and motivating them. 9. Include information about community service. If all students knew that employers appreciate community service as an activity that shows that the person has matured and cares for the society, they wouldn’t underestimate it so much. Make sure to include information about your activities as a volunteer – your potential employers will definitely appreciate it. 10. Review before you submit! Your resume will require some serious reviewing before you can send it safely to employers. This isn’t the place where you can allow spelling and grammatical errors to slip through. The best advice would be to hire a professional editor to bring this important document to perfection. One of the most important things to remember is that writing a great resume requires a lot of time and devotion. Make sure to follow the above-listed steps, and you will make the entire process less daunting.
over 5 years ago
This video - produced by students at Oxford University Medical School in conjunction with the faculty - demonstrates how to deliver oxygen therapy through various devices, as well as the prescribing of oxygen.<br>It is part of a series of videos covering Respiratory Medicine skills.<br><br>Please see the BTS guidelines for more information:<br><a href="http://www.brit-thoracic.org.uk/guidelines/emergency-oxygen-use-in-adult-patients.aspx" target="_blank" title="http://www.brit-thoracic.org.uk/guidelines/emergency-oxygen-use-in-adult-patients.aspx" rel="nofollow" dir="ltr" class="yt-uix-redirect-link">http://www.brit-thoracic.org.uk/guidelines/emergency-oxygen-use-in-adult-pati...</a>
about 7 years ago
Introduction Computerised presentations are a part of every medical student's / junior doctor's life. Sometimes we give them, often we sleep through them and occasionally we even listen to them. They are the backbone of medical education besides traditional bed-side teaching, having rapidly replaced the now extinct OHR (Over Head Projector) acetate-sheet presentations of years gone-by. The problem is that Doctors and medical students often struggle with creating and presenting coherent slides. This is most probably due to the general apathy most have for actually talking in front of an audience, or because those asked to present are often taken unawares, and therefore have little time to prepare. In these times of avolition or last-minute hurriedness, people often reach out for the industry standard of presentation production: PowerPoint. PowerPoint is the most commonly used tool for making presentations because it is simple to use and comes with a whole load of free templates. Unfortunately, most of these templates look disgusting. If a template doesn't look disgusting, then it is most certainly overused and you run the risk of having a presentation that looks identical to the student before you at the weekly seminar teaching - a scenario that can be easily likened to turning up to a lecture wearing exactly the same clothes as another person in the room, which would just be awkward. Another problem with PowerPoint is the phenomenon of 'Death By Powerpoint,' which refers to the general boredom and apathy experienced by those who have received way too much information in way too short a space of time via a series of over-cramped, poorly stylised slides. But why on earth do you care? People should care about 'Death By Powerpoint' because if your presentations cause people to zone out, then you are not getting your message across. And if you aren't getting your message across then you. are. not. presenting. at. all. (take a moment to reflect on that particularly Zen statement). Let me explain using a metaphor, if I am a sales person and I present my talk with well-designed slides, in an enthusiastic and well-rehersed manner to an appropriate audience I will make more sales than if I present using poorly designed slides at the last minute. Similarly, in Medicine if I present well designed, aesthetic slides I am more likely to convey accurate information to my colleagues that may very well be retained and enjoyed by all involved. Of course, this blog assumes a degree of presentation-related Altruism. The recommendations I am about to make require you to 'step out of the mould' and say 'no' to poor presentations. They require you to forgive others for the presentations they have inflicted on you in the past. You will 'lead by example'. Unfortunately I am not capable (or qualified) to make you an excellent designer, nor can I give you the motivation to feel as passionately about design aesthetics as i do when all you've got to do is slam some slides together for your monthly journal club. But what I can do is present to you a series of resources that might tempt you away from the horrific PowerPoint templates that currently infest medical student seminars and young doctors presentations. If you really couldn't care less, then I suggest using Prezi, a website where you can make quite eccentric looking presentations rapidly and for free. The only problem is that Prezi became cliched even before its debut and you risk inflicting travel sickness on your poor audience, what with all the funky zooming in and out of slides that occurs during a typical Prezi presentation (you will know what I mean if you've ever seen one). So, without further ado, here are my top 5 tips for making your presentations look smoother and more polished... Irrespective of whether the contents of your talk are any good. Step One: Typography Get yourself a good font. Typography is really important, when you speak to someone you use a variety of tones and gestures to convey the meaning of the words you are using. Fonts are effectively the printed version of your tone and gestures. Good font choice can help give 'umph' to a particular point in your presentation and help give character to what you are saying. Of course, it's important to remain professional so 'Wingbats' might not be your first choice, but anything that you could envisage on a nice business card is probably a good shout. Fonts are usually something you have to pay for if you want anything beyond the set given to you when you download Microsoft Word (for example). However, there are whole hosts of free fonts available from sites like [dafont])(http://www.dafont.com). The key is to be willing to trawl through these sites to find fonts that are actually useful! Beware those fancy fonts unless you know your audience can take it! If you are stuck on choosing a font, which is a common complaint, then maybe this flow diagram will help! Oh yeah, and never ever use Comic Sans. Ever. Step Two: Colour A good font isn't going to get you very far on its own. You need a solid colour scheme to bring your presentation alive. It seems blunt to say, but some people are not very good at picking colours that go well with one another. This is well evidenced in PowerPoint presentations where the yellow-text-on-blue-background is far too common. I mean yeah, in theory blue and yellow 'compliment' each other, but thats where the relationship between blue and yellow should stay... in theory. Luckily there are some useful colour palette websites available out there, which will match colours for you... Step Three: Structure After you've picked a sensible font and a suitable colour scheme, it's time to think about the structure or layout of your slides. It's absolutely crucial that you avoid putting too much information on your slides even if you are giving an academic presentation. An overloaded slide is about as useful as a dead cat. At this point, some of you may be tempted to resort to those dodgy PowerPoint default templates but there is another way! There are sites out there that have some pretty fresh templates you can use and they are completely free! They are sure to add a bit of spice to your slide's aesthetic. There will probably be a separate tutorial on this in the future, but basic principles apply. As a general rule stick to Left Alignment *and avoid *Central Alignment like the plague. Step Four: Imagery Images help to spice up a presentation, but try and keep them related to the topic. Google Images is a great resource but remember that most images will be a low resolution and will be poorly suited to being shown blown up full-size on a presentation screen. Low resolution images are a presentation killer and should be avoided at all costs. For high-quality images try sites like Flikr or ShutterStock. Step Five: Consider Software The interface of Powerpoint does not lend itself well to having images dropped in and played with to make nice looking layouts. I would recommend Adobe Photoshop for this kind of work, but not everyone will have access to such expensive software. Cheap alternatives include Photoshop Elements amongst others. Once you have created slides in Photoshop it is quick and easy to save them as JPEG files and drag and drop them into PowePoint. Perhaps that can be a tutorial for another time... Step 5: Additional Stuff Presentations typically lack significance, structure, simplicity and rehearsal. Always check over your presentation and ask 'is this significant to my audience?' Always structure your presentation in a logical manner and (it is recommended you) include a contents slide and summary slide to tie things together. Keep your verbal commentary simple and keep the slides themselves even more simple than that. Simplicity is crucial. Once you have produced your beautiful slides with wonderful content you will want to practice them. Practice, Practice, Practice. Rehearsing even just once can make a good presentation even better. Conclusion: This blog entry has covered some basic points on how to improve your medical presentations and has given a series of useful online resources. Putting effort into designing a presentation takes time and motivation, for those without these vital ingredients we recommend Prezi (whilst it is still relatively new and fresh). Perhaps the rest of you will only use these tips for the occasional important presentation. However, I hope that soon after you start approaching presentations with a little more respect for their importance and potential, you too will find a desire to produce high-quality, aesthetically pleasing talks. LARF - Mood: damn tired and feeling guilty that I just wrote this blog instead of revising haematology notes. Follow me on Twitter. Follow the Occipital Designs original blog. Check out my Arterial Schematic.
Dr. Luke Farmery
over 6 years ago
Introduction This post describe the creation of a Stroke Summary video. The aim of this project was to assess the attitudes of medical students towards the use of video animation in medical education. An educational tutorial was produced outlining the basic principles of stroke. This aimed to provide a summary of different aspects relating to stroke, outlined in the Bristol University curriculum. This intended to be a short, concise animation covering stroke presentation, definition and recognition, with an overview of the blood supply to the brain and the classification of stroke presentation used in clinical practice. This was followed by some key facts and a summary of different management stages. After the video animation was produced an assessment of student’s attitudes using an online questionnaire was undertaken. This consisted of ten short questions and an open text feedback for additional comments. The video was then edited with reference to feedback given by students and the results analysed. This report will outline relevant research and project work that lead to this assignment being undertaken. A description of the method followed to generate the video animation and to collect feedback on students will be outlined followed by analysis of results. This will then be discussed in relation to previous work and research. Background There are a number of reasons this project has been undertaken. On a personal level, I have a long-standing interest in teaching and medical education. As part of a previous project I created a series of audio tutorials in cardiovascular medicine and assessed student attitudes to audio learning. The findings of this report showed that a large number of students found these audio tutorials useful and would like more of these available to supplement their learning. One of the questions given to students at this time assessed how useful they found different types of educational material. This project showed students reporting audio tutorials more useful than previously thought, while also reporting that they were not readily available. Although a video tutorial was not provided to them at this time, feedback questions assessed attitudes to video tutorials as a learning resource. Students reported low availability and felt they would be more useful than audio tutorials. Some results from this project are shown in figure 1. Figure 1. Results from previous research by Buick (2007), showing attitudes of students towards different learning tutorials. The majority of students report audio tutorials to be ‘quite useful’ or ‘very useful’. Video tutorials are thought by students to be more useful that audio tutorials, however there is a large proportion that do not have access to these learning resources. As a number of students reported an inability to access to video tutorials, it was thought that creating a video animation tutorial followed by assessing students attitudes would be a useful follow up project. If this is found to be a useful resource, other students may generate video tutorials in the future. Therefore student feedback also assessed attitudes towards authenticity, relating to who generates the tutorial and whether they find the ability to feedback a useful tool. Medical education is widely researched globally, although it is not often a consideration for those studying medicine. Those involved in teaching and educating future doctors have looked at different methods of passing on knowledge. A high quality medical education given to future healthcare professionals is important. It is widely accepted that a better knowledge results in better care for patients and education is at the centre of any healthcare system. This is reflected in the cost of educating medical students and training doctors in the UK. In the 1997 it was reported by the Department of Health that estimates of 200 million pounds would be spent per year for an increase in 1000 medical students being trained in the UK. This suggests that the cost of training a medical student is in the region of £200,0001. Medical education in the UK is split in two halves, with undergraduate and postgraduate training. The Department of Health has recently invested millions of pounds into the development of online tutorials for postgraduate training posts in a number of different specialities. Justification for is given by reducing the cost of training through the use of standardised online tutorials. This will be a more cost effective method than the standard in hospital teaching. This approach has not been undertaken for undergraduate medical education. Universities are seen as primarily responsible for undergraduate training. Many of these institutions have used the Internet to aid teaching and have produced video tutorials. However, as reflected in the previous project (Buick, 2007), resources are often limited and students do not feel they have ready access to these educational tutorials. The benefits of different types of learning resource have been researched. These include online audio downloads (Spickard et al, 2004), practice exam questions and interactive tutorials (Hudsen, 2004). Research showing the benefit of video was shown by Balslev et al (2005) comparing video and written text while teaching a patient case. Balsley et al (2005) found those who learnt using a video presentation rather than those given written text showed a significant increase in data exploration, theory evaluation and exploration. However, there is little research looking specifically at video animation for explaining conditions. Animation software is now available on personal computers and is also possible using Microsoft PowerPointTM, which is the most widely used presentation software. It is clear that recent trends show training can benefit from this type of learning resource. Generation of high quality video tutorials can help students learn while reducing the cost of training. It is for this reason that more material is likely to become available, either from funded production supported by external organisations or by the trainers and trainees themselves who have technology able to produce material such as this on their home computer. Ethical and Legal Issues During the development of this video some ethical and legal issues arose that had to be addressed before a final video could be made. When considering what imagery would be used in the video, I wanted to include pictures of clinical signs relevant to the audio narration. However, taking images from the Internet without prior consent was not thought to be ethical and therefore clinical signs were displayed graphically through drawings and diagrams. Plagiarism and copyright were some of the legal issues surrounding the presentation of medical information. Narrated information was generated using a number of information sources, none of which were exclusively quoted. Therefore an end reference list was generated showing all supporting information sources. Images used in the animation were either self generated or taken from sources such as Wikipedia.org. This resource supplies images under a free software license such as GNU general public license2. This allows anyone to freely use and edit images while referencing the original source. Skills Needed To Develop This Video Animation To generate the video a number I had to develop a number of new skills. Unlike previous work that had been undertaken this media was generated using animation software. To use this effectively I had to research the different functions that were available. To do this I combined reading books aimed to teach beginners such as Macromedia Flash 8 for Dummies (Ellen Finkelstein and Gurdy Leete, 2006) and online sources such as www.learnflash.com . To generate voice narration, another program was used that allowed editing and splicing of audio tracks. This was then split up into a number of narrated sections and added to the animation. Method Script To produce the tutorial the first stage was to construct a script for narration. This involved outlining the areas to be covered. The main headings used were: Stroke definition This gave a clinical definition and a lay person recognition mnemonic called FAST which is used to help members of the general public recognise stroke. Pathophysiology This covered blood supply to the brain. This combined diagrams of the circle of Willis, with images of the brain. Arterial blood supply were then displayed over the brain images while relating this to the arterial vessels leaving the circle of Willis Classification Students at Bristol university are asked to understand the Oxford / Bamford classification. This was covered in detail with explanations of clinical signs that may be seen and graphical representation of these. Prevalence This section covered prevalence, national impact and cost of stroke in the UK. Management In this section management was split up it to immediate management, medical management, in hospital care and some of the procedures considered for different cases. Risk factors for stroke and research into this was also written up and narrated. However at a later stage this was not included due to time constraints and video length. Narration An audio narration was generated using software called ‘Garage Band’ which allows audio tracks to be recorded and edited. The narration was exported in 45 sections so that this could then be added to the animation at relevant points. Animation The animation was made using Adobe Flash. This software is used for making websites and animations used for Internet adverts. It has the facility to export as a ‘flash video format’, which can then be played using a media player online. This software generates animation by allowing objects to be drawn on a stage and moved around using command lines and tools. This was used as it has the ability to animate objects and add audio narration. It also is designed for exporting animations to the Internet allowing the material to be accessed by a large number of people. Feedback A short questionnaire was generated which consisted of ten questions and placed online using a survey collection website (www.surveymonkey.com). Students were directed to the feedback questionnaire and allowed to submit this anonymously. Adapting the tutorial Some feedback constructively suggested changes that could be made. The video was updated after some concern about the speed of narration and that some of the narrative sections seemed to overlap. Analysis and Report The results of the feedback were then collected and displayed in a table. This was then added to the report and discussed with reference to research and previous project work. Results Students were allowed to access to the video animation through the Internet. After uploading the video an email was sent to students studying COMP2 at Bristol University. These students are required to know about aspects of stroke covered in this tutorial to pass this section of the course. The email notified them of the options to view the tutorial and how to give feedback. In total 30 students completed the feedback questionnaire and out of these 4 students provided optional written feedback. The results to the questions given were generally very positive. The majority of students showed a strong preference to video animations as a useful tool in medical education. The results are displayed in Table 1 below. TABLE 1 shows the ten question asked of the students and to what extent they agreed with each statement. Results are given in the percentage of students who chose the relevant category. Written Feedback Four written comments were made: "Really useful presentation!! Would be much better if someone proof read the whole thing as there are some spelling mistakes; also if the pauses between facts were longer it would be more easier to take in some facts. Overall, really nicely done!!" "Some of speech went too quickly, but good overall" "Very clearly written with excellent use of images to match the text and commentary!" "The Video was excellent." Discussion Student attitudes to this video tutorial were very positive. This was in contrast to the attitudes previously shown in the audio tutorial project (Buick, 2007) where video tutorials were not thought to be a useful resource. These results support recent developments in the generation of online video training for doctors by the Department of Health and previous research by Balsley et al (2005). Question one showed that the majority of students strongly agreed that the stroke video would be a useful resource. Questions two, three and four aimed to establish what aspects of a disease were best outlined using a video animation. Results showed that students agree or strongly agreed that defining the condition, pathophysiology and management were all well explained in this format. Interestingly, a large majority of students (70%) felt pathophysiology was best represented kinaesthetically. This may be due to the visual aspect that can be associated with pathophysiology. Disease processes are often represented using diagrams in textbooks with text explaining the disease process. Using computer technology it is possible to turn the text into audio narration and allow the user to view dynamic diagrams. In this way, students can better conceptualise the disease process, facilitating a more complete understanding of disease and its clinical manifestations. Question five aimed to highlight the benefit of visual stimulation as well as audio narration as a positive learning method. All students agreed or strongly agreed that the combination of these two aspects was beneficial. Question six showed a very strong response from students wanting access to more video tutorials, with 70% of students strongly agreeing to this statement. It is often the case that students take part in generating teaching material, and some students may be concerned that this material is inaccurate. However, many students do not think that this is a significant problem. This is reflected by the spread of student’s opinion seen in question 7, where there was no clear consensus of opinion. It may be that as students learn from a number of different resources, that any inaccuracies will be revealed and perhaps stimulate a better understanding through the process of verifying correct answers and practicing evidence based medicine. Question nine and ten show that most students value resources that allow sharing of educational material and feel they could help others learn. They would also value the option to feedback on this material. The written feedback showed positive responses from students. However there was feedback on some aspects of the video that they felt could be changed. The narration was delivered quickly with few gaps between statements to keep the tutorial short and concise, however this was thought to be distracting and made it less easy to follow. Following this feedback the narration was changed and placed back on the Internet for others to review. Further research and investigation could include the generation of a larger resource of video animations. My research has suggested that using animation to cover pathophysiology may be most beneficial. The software used to make this video also allows for the incorporation of interactive elements. The video produced in this project or other videos could have online menus, allowing users to select which part of the tutorial they wish to view rather than having to watch the whole animation, or they include interactive questions. Reflections Strength and weaknesses Strengths of this project include its unique approach to medical education. There have been few animated videos produced for undergraduate medical students that use this advanced software. This software is used by professional web developers but can be used effectively by students and doctors for educational purposes to produce video animation and interactive tutorials. For these reasons, I passionately believe that this technology could be used to revolutionise the way students learn medicine. If done effectively this could provide a more cost effective and engaging learning experience. This will ultimately benefit patients and doctors alike. This material can be place online allowing remote access. This is increasingly important for medical students studying on placements who are often learning away from the university setting. Weaknesses of this project include that of the work intensity of generating animated video. It is estimated that it takes around 6 to 9 hours to produce a minute of animated video. This does not include the research and recording of narration. The total sum of time to generate material and the additional skills needed to use the software makes generation of larger numbers of videos not possible by a small community of learners such as a university. Although it was done in this case, it is difficult to edit the material after it has been created. This may mean that material will become inaccurate when new advances occur. The feedback sample collected was opportunistic and the response rate was low. These factors may bias the results as only a subsection of opinions may have been obtained. These opinions may not be representative of the population studied or generalisable to them. It was difficult obtaining a professional medical opinion about the video in the time that I was allocated. However this has been organised for a later time. Knowledge and skills gained During this project I was able to learn about stroke its presentation, classification, management and risk factors. I read texts, which summarised stroke and research into risk factors and management of stroke. The challenge of usefully condensing a subject into a short educational tutorial was a challenging one. I feel I improved my skills of summarising information effectively. I gained knowledge of some of the challenges of undertaking a project such as this. One of the largest challenges included how long it took to produce the animation. In the future I will be aware of these difficulties and allow for time to gather information and generate the material. I also learnt the benefit of gaining feedback and allowing for adaption to this. It took more time to respond to feedback but this resulted in a better product that other students can use. I also reflected on the impact of stroke itself. Stroke has a major impact on patients, health care and carers. Much can be done in the recognition classification and management. A better understanding benefits all areas and I have gained a better knowledge and the importance of helping others gain a good understanding of stroke. I learned how to generate a video animation for the use of teaching in medicine and combine this with audio presentation. I learned how long it can take to generate material like this and the skill of organising my time effectively to manage a project. I can use this skill in the future to produce more educational material to help teach during my medical career. I also gained skills in learning how to place material on the Internet for others to access and will also use this in the future. Conclusions Previously evidence has shown the use of videos in medical education to be beneficial. It has normally been used to demonstrate clinical examination and procedures this study suggest there is a place for explanation of pathophysiology and disease summaries. However, there has been little research in to its use for graphically representing condition summaries. Computer technology now allows people to generate animation on their personal computer. It is possible that over time more students and doctors will start producing innovative visual and audio teaching material. This project indicates that this would be well received by students. References Planning the Medical Workforce: Medical Workforce Standing Advisory Committee: Third Report December. 1997 Page 40. The GNU project launched in 1984. Balslev T, de Grave W S, Muijtjens A M and Scherpbier A J (2005) Comparison of text and video cases in a postgraduate problem-based learning format Medical Education; 39: 1086–1092 Buick (2007) Year 3 External SSC. Bristol University Medical School. Spickard A, Smithers J, Cordray D, Gigante J, Wofford J L. (2004) A randomised trial of an online lecture with and without audio; Medical Education 38 (7), 787–790. Hudson J. N., (2004) Computer-aided learning in the real world of medical education: does the quality of interaction with the computer affect student learning? Medical Education 38 (8), 887–895. Ellen Finkelstein and Gurdy Leete, (2006) Macromedia Flash 8 for Dummies. Wiley publishing Inc. ISBN 0764596918
Dr Alastair Buick
over 9 years ago
Designed by Dr. Todd Ravins & Stephen Weisz. Graphics by Gina Fiore. Source: http://beejweir.tumblr.com/post/25441127256/toothorgan-relationship-chart-includes-glands
almost 4 years ago
http://www.handwrittentutorials.com - This is the second tutorial in the Renal Anatomy series. This video explores the anatomy of the Nephron, and its component elements. For more entirely FREE tutorials and their accompanying PDFs, visit http://www.handwrittentutorials.com
over 5 years ago
This is an excerpt from "Fluids and Electrolytes Made Incredibly Easy! 1st UK Edition" by William N. Scott. For more information, or to purchase your copy, visit: http://tiny.cc/Fande. Save 15% (and get free P&P) on this, and a whole host of other LWW titles at lww.co.uk when you use the code MEDUCATION when you check out! Introduction The chemical reactions that sustain life depend on a delicate balance – or homeostasis – between acids and bases in the body. Even a slight imbalance can profoundly affect metabolism and essential body functions. Several conditions, such as infection or trauma, and certain medications can affect acid-base balance. However, to understand this balance, you need to understand some basic chemistry. Understanding pH Understanding acids and bases requires an understanding of pH, a calculation based on the concentration of hydrogen ions in a solution. It may also be defi ned as the amount of acid or base within a solution. Acids consist of molecules that can give up, or donate, hydrogen ions to other molecules. Carbonic acid is an acid that occurs naturally in the body. Bases consist of molecules that can accept hydrogen ions; bicarbonate is one example of a base. A solution that contains more base than acid has fewer hydrogen ions, so it has a higher pH. A solution with a pH above 7 is a base, or alkaline. A solution that contains more acid than base has more hydrogen ions, so it has a lower pH. A solution with a pH below 7 is an acid, or acidotic. Getting your PhD in pH A patient’s acid-base balance can be assessed if the pH of their blood is known. Because arterial blood is usually used to measure pH, this discussion focuses on arterial samples. Arterial blood is normally slightly alkaline, ranging from 7.35 to 7.45. A pH level within that range represents a balance between the concentration of hydrogen ions and bicarbonate ions. The pH of blood is generally maintained in a ratio of 20 parts bicarbonate to 1 part carbonic acid. A pH below 6.8 or above 7.8 is usually fatal. Too low Under certain conditions, the pH of arterial blood may deviate significantly from its normal narrow range. If the blood’s hydrogen ion concentration increases or bicarbonate level decreases, pH may decrease. In either case, a decrease in pH below 7.35 signals acidosis. Too high If the blood’s bicarbonate level increases or hydrogen ion concentration decreases, pH may rise. In either case, an increase in pH above 7.45 signals alkalosis. Regulating acids and bases A person’s well-being depends on their ability to maintain a normal pH. A deviation in pH can compromise essential body processes, including electrolyte balance, activity of critical enzymes, muscle contraction and basic cellular function. The body normally maintains pH within a narrow range by carefully balancing acidic and alkaline elements. When one aspect of that balancing act breaks down, the body can’t maintain a healthy pH as easily, and problems arise.
Lippincott Williams & Wilkins
over 6 years ago